Single Strip - Double Web Ceiling Grid Member

ABSTRACT

A runner for a suspended ceiling grid is roll-formed from a single strip of sheet metal so as to have a generally symmetrical appearance about a vertical center line, with a double vertical web and a double-thickness flange for supporting ceiling tiles. The bottom surface of the flange is continuous across its exposed surface, so that there is no visible juncture of the opposed flanges with the double web when viewed from below, thus providing an aesthetically more-pleasing appearance.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.11/612,002, filed Dec. 18, 2006 which claims the benefit of the filingdate of U.S. Provisional Application Ser. No. 60/751,866, filed Dec. 20,2005, which is incorporated herein by reference, and which is acontinuation-in-part of U.S. application Ser. No. 11/499,035, filed Aug.4, 2006, which claims the benefit of the filing date of U.S. ProvisionalApplication Ser. No. 60/705,758, filed Aug. 5, 2005.

BACKGROUND OF THE INVENTION

The present invention relates to a grid member, commonly referred to asa runner or tee, for use in a suspended ceiling system for supportingceiling tiles. A typical grid tee construction includes a metal stripformed into an upper strengthening bulb or bead, a vertical,downwardly-extending double web, and lower, oppositely-extendingflanges. The exposed or lower surface of the flanges is not continuous.That is, there is a transition visible between the flanges where theyextend from their respective vertically-extending web member. Thistransition is often considered to be aesthetically unpleasing, and a capmember is applied to the diverging flanges to cover the transition andprovide a more finished appearance to the grid tee, as well as toprovide additional resistance to spreading of the flanges. As can bereadily appreciated, the addition of the cap member adds to the cost ofthe grid tee both due to additional material costs and the requiredroll-forming steps for applying the cap member, and also increases theweight of the grid tee.

Accordingly, it is an object of the present invention to provide a gridtee for a suspended ceiling system in which the tee is made from asingle strip of sheet metal but does not require a cap member foraesthetic or structural reasons.

SUMMARY OF THE INVENTION

According to the present invention, a runner or tee is roll-formed froma single strip of sheet metal so as to have a generally symmetricalappearance about a vertical center line, with a double vertical web anda double-thickness flange for supporting ceiling tiles. The bottomsurface of the flange is continuous across its exposed surface. That is,there is no visible juncture of the opposed flanges with the double webwhen viewed from below, thus providing an aesthetically more-pleasingappearance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a ceiling grid member according to thepresent invention in which the reinforcing bead includes a fin extendingupwardly therefrom.

FIG. 2 is a first alternate embodiment of the ceiling grid member ofFIG. 1 in which the fin is formed with a lock seam.

FIGS. 3-7 are further alternative embodiments of the grid member of FIG.2 that differ in the configuration of the lock seam formed in the fin.

FIGS. 8 and 9 are alternate embodiments of the ceiling grid memberaccording to the present invention in which the upper portion of thevertical web is configured with slots.

FIGS. 10-13 are alternate embodiments of a ceiling grid member accordingto the present invention in which the strengthening bead is formed so asto give the cross-section a configuration more like a traditionalI-beam.

FIGS. 14 and 14A are alternate embodiments of a grid member according tothe present invention in which the grid member does not have astrengthening bulb at the upper end thereof.

FIGS. 15 and 15A are similar to FIGS. 14 and 14A except that the gridmembers include a cap member of affixed to the flanges.

FIGS. 16 and 16A are alternate embodiments of the grid members of FIGS.14 and 14A in which the flanges are configured to form a bolt slot.

FIG. 17 is a perspective view of a beam in which the fin includes a holefor receiving the hanger wire for suspending the beam.

DETAILED DESCRIPTION

Grid members for suspended ceilings are well-known in the art, asexemplified by the runners or tees shown in U.S. Pat. Nos. 4,525,973,4,549,383, 4,601,153, 4,677,802 and 4,785,595, all incorporated hereinby reference and all having the same assignee as the present invention.Such runners or tees are roll-formed from an elongated strip of sheetmetal into a configuration having a strengthening bead or bulb at theupper end, a web extending vertically downward from the bead, andopposed flanges at the lower end of the web.

With reference to FIGS. 1-7, profiles of grid members, according to thepresent invention, generally designated 10, are seen. These grid members10 have the same structural features as the typical runners or tees,namely, an intermediate vertical web 12 having a bead 14 at its upperend and opposed flanges 16, 18 at its lower end.

In keeping with the invention, the grid members 10 are roll-formed froma single elongated strip of sheet metal such that the opposed side edgesof the strip are located at the reinforcing bead 14. This results in thevertical web 12 of the runner 10 having a double thickness and the lowersurface of the flanges 16, 18 being continuous. Specifically, there isno seam between the opposed flanges where they join the vertical webthat is observable from below, as is typically found in prior art gridmembers that have a double thickness vertical web.

Turning specifically to FIGS. 1-7, the grid member includesstrengthening bead or bulb 14 that preferably, but not necessarily,includes a generally vertically-extending “fin” 20 to provide increasedbeam height and, thus, increased resistance to bending. Such areinforcing fin is discussed in copending application Ser. No.11/499,035, filed Aug. 4, 2006, which is incorporated herein byreference. The fin configuration permits the runner to be formed ofthinner material than prior art runners not having such a fin withoutcompromising the beam strength of the runner. This results in a runnerthat is more economical to manufacture (because less material isrequired), is easier to handle (particularly in bulk or cartonquantities to each runner is lighter in weight), and is easier to cut.

As shown in FIG. 17, the fin 114 is preferably provided with a series ofspaced holes 122 for receiving the hanger wire 124 for suspending theassembled grid from the ceiling. Preferably, the series of holes 122 isspaced so that a hole 122 is aligned with apertures in the web of thebeam for receiving the cross beams. Having the fin 114, rather than theweb 116, carry the hanger wire allows for the hanger wire to be alignedwith the cross-tee and for the hanger wire to be more tightly wrappedabout itself. This, in turn, lessens the likelihood of damaging theedges of the ceiling tiles by the hanger wire when the tiles are droppedinto place on the flanges 126 of the runner 110 because there is greaterclearance. The greater clearance also facilitates faster installation ofthe ceiling tile. The hanger holes 122 are also preferably formed aspart of an embossment for additional strength. The embossment alsoprovides a tapered hole, which allows easier hanger wire insertion.

With specific reference to the embodiments of FIGS. 2-7, the fin 20includes a lock seam in which at least a portion of the fin 20 is bentback on itself. The lock seam provides increased resistance to torsionand buckling, and thus increased ultimate load resistance. Forming thelock seam “work hardens” the material in the local area, thus enhancingthe overall mechanical properties of the runner. With reference to FIG.2, the lock seam has a triple thickness of sheet material, with a firstedge of the sheet metal strip from which the grid member is formedextending beyond the second edge and the first edge being bent over thesecond edge. With reference to FIG. 3, the lock seam has a quadruplethickness, with the first edge and second edge of the sheet metal stripmeeting and both edges being bent back over the second edge. The lockseam of the FIG. 4 embodiment also has a quadruple thickness. However,the second edge is first bent downwardly toward the center of the beadand then the first edge is bent over the top of the fold in the secondedge. The embodiments of FIGS. 5-7 are similar to that of FIG. 4, exceptthat the second edge extends into the interior of the bead (FIG. 5); orthe second edge lies against the interior of the bead (FIG. 6); or thesecond edge lies against the interior of the bead and the first edgelies against the exterior of the bead (FIG. 7).

With reference to embodiment of FIG. 14, a further alternative for a tee14 according to the present invention is shown. This alternative doesnot include a strengthening bulb or bead. As shown in FIG. 14A, if thetee has no bulb or lock seam at the upper end of the web, astrengthening stitch 22 in the vertical web may be desirable to maintainthe structural integrity of the tee. Such a stitch or mechanicalinterlock 22 is well known in the art, as shown by, e.g., U.S. Pat. Nos.5,577,313, 5,979,055 and 6,047,511, and also may be used in theembodiments of FIGS. 1-7. Alternatively, the vertical webs can be weldedor otherwise fastened to each other (as by an adhesive).

While not required, a cap 24 can be applied to the flanges foradditional strength or for aesthetic reasons, as seen in embodiments ofFIGS. 15 and 15A, which otherwise are identical to the embodiments ofFIGS. 14 and 14A. In a further alternative, instead of an opposedflanges for supporting ridges of ceiling tiles, the lower portion of therunner can be provided with a bolt slot profile 26, as seen in theembodiment of FIGS. 12 and 12A. Previous designs having a bolt slotrequired the profile to be roll formed from pre-painted strip withfinish colors on both sides of the strip. The embodiments of FIGS. 16and 16A require the strip to be painted on one side only, thus providinga cost reduction.

Alternate bulb configurations 14 are seen in the embodiments of FIGS. 8and 9. The open lower portions of the bulb permit the use of accessoryclips. Specifically, the lower horizontal flange of the bulbs do notextend to the vertical web, creating a slot or a gap 28 that allows thelower end of a clip to be received and retained by the bulb, orotherwise facilitates suspension of the tee. The embodiments of FIGS. 8and 9 also utilize a stitch 22 through the upper portion of the verticalweb 12 to help maintain profile geometry and strength. The stitch 22 isconcealed, thus resulting in improved aesthetics of the profile.

FIGS. 10-13 show further embodiments of grid members 10 according to thepresent invention in which the strengthening bead 14 is formed to have agenerally flat configuration that lies in a plane that is substantiallyparallel to the plane defined by the flanges 16, 18, so as to be morelike an I-beam in appearance. This results in the grid members of FIGS.10-13 being easier to roll form. Further, the distance that the materialdefining the bead is spaced from the flanges is maximized, thusmaximizing the load rating for the grid members while utilizing theleast amount of material. Each of the embodiments of FIGS. 10-13 alsoincludes a stitch 22 in their vertical webs 12 to help maintain theintegrity of the grid geometry.

Turning specifically to FIG. 10, the strengthening bead 14 is formed bybending the edges of the strip so as to be generally perpendicular tothe vertical web and then bending the edge downwardly back on itself.The strengthening bead 14 in the embodiment of FIG. 11 is formedsimilarly, except that the edges are bent upwardly back on themselves,and the edges meet along the vertical center line of the grid member.The strengthening bead 14 in the embodiment of FIG. 12 is similar tothat of FIG. 10, except the edges are bent back on themselves twice,resulting in the strengthening bead 14 to have a triple thickness ofsheet material. The strengthening bead 14 in the embodiment of FIG. 13is similar to that of FIG. 12, except that the edges are bent upwardly.

Thus, a single strip ceiling grid member has been provided that meetsthe objects of the present invention. While the invention has beendescribed in terms of certain specific embodiments, there is no intentto limit the invention to the same. Instead, the invention is defined bythe following claims.

1-9. (canceled)
 10. A roll-formed grid member for a suspended ceilingmade from metal strip, the member being generally symmetrical about animaginary vertical plane and having a cross-section that includes alower horizontal flange extending laterally on both sides of theimaginary plane, the flange being formed of said metal strip, agenerally vertical stem formed of two layers of said metal strip, onestem forming layer on each side of said imaginary plane, said stemforming layers being immediately adjacent one another in the proximityof said flange so that the edges of ceiling panels can fully rest onsaid flange adjacent to and on opposite sides of said imaginary planeand being separated from one another at a distance above said flange toform a reinforcing bulb, said stem forming layers being in abuttingcontact in a zone above said reinforcing bulb, and alignedlongitudinally spaced apertures in said layers in said contact zone forreceiving loops of suspension wires, said contact zone above saidapertures being free of overlying structure of said grid member whichwould otherwise require the loops of suspension wires to be wider thanthat required by said contact zone.
 11. The roll-formed grid member asset forth in claim 10, wherein one of said stem forming layers in saidzone is folded to form an additional layer in said zone.
 12. A gridmember of a suspended ceiling comprising a body generally symmetricalabout an imaginary central vertical plane and having a cross-sectionthat includes a lower horizontal flange extending laterally on bothsides of the central plane and a stem extending vertically above saidhorizontal flange, the stem including a narrow portion above the flange,a hollow bulb portion wider than and above the narrow portion, and anupper portion above the bulb portion, the upper portion beingsubstantially free of air space whereby it is laterally thinner thansaid bulb portion, said upper portion having longitudinally spaced holesfor receiving suspension wires, the difference in width between theupper and follow stem portions enabling a suspension wire look formed bypassing a suspension wire through a hole in the upper portion to besubstantially narrower than a suspension wire loop passing through oraround said bulb portion.